add core guest step by step on active standby guest

hi expert 

i want to makesure step by step how to add core on guest active standby

1. makesure all guest on standby mode 

2. change guest deploy to configure

3. add core ion guest

4. change guest configure to deploy 

5. failover on guest active to standby

should i sync group to manual to avoid impact on existing or just ignore it on pre activity 

thanks